This invention relates generally to dispensing systems for potable water and more particularly to an improved, air gap drain module for use in a reverse osmosis system or preferably in a reverse osmosis dispensing system for potable water.
Reverse osmosis systems referred to alternatively herein as R/O Systems, applied to the purification of water are known in the art. Their use is expanding rapidly for the production of relatively small quantities of potable water for household uses.
Such reverse osmosis systems under normal operating conditions produce a continuous flow of waste water which has a high salt content and this waste water or brine must have a continuous drainage facility for removing this process water from the reverse osmosis system. In this respect for the safety of the system and to meet laws and ordinances of towns and municipalities particularly where such drainage facilities are connected to the sewer system, an adequate anti-syphon means is required to prevent the possibility of sewage or tainted water backing into the R/O System through the drain for the waste water or brine. Generally this is in the form of a 1" or more air gap in the drain line at a point or at a specified height above the valve mounting surface or waste water basin overflow plane.
The use of a separate and independent air gap or anti-syphon devices for R/O Systems for potable water are shown in U.S. Pat. Nos. 3,183,923 and 3,455,324 and illustrate one means of meeting and overcoming this problem.
However in order to avoid the expense of and the additional installation requirements of a separate air gap fixture, combination dispensing heads with integral air gap units to meet the requirements of the law and ordinances and to make these drainage facilities acceptable and safe for the users of an R/O System have been developed and used as is shown in U.S. Pat. Nos. 3,620,241 and 3,967,638.
The present invention provides an improved air gap drain module which permits the standard dispensing head to be so modified that it can be used either as a conventional dispensing head or carafe filler or alternatively and selectively as a combined dispensing head and air gap drain module which is particularly adaptable for use with the R/O Systems for providing purified water.
The standard dispensing head formed in accordance with the present invention is provided with an auxiliary bore into which the air gap drain module in accordance with the present invention can be removably connected. Further, by reason of this construction, the air gap drain module can be furnished with the associated connecting lines, normally plastic tubing, which is preassembled so that the air gap drain module can be easily installed in the field by snapping the same into assembled position in the modified standard dispensing head and connecting the drains to the drainage facility at the installation site.